Articulation mechanism for surgical stapling device

ABSTRACT

A surgical device includes an adapter assembly and a tool assembly that is coupled to the adapter assembly by a pivot member to facilitate articulation of the tool assembly in relation to the adapter assembly. The adapter assembly supports a drive assembly for actuating or firing the tool assembly. The adapter assembly includes an articulation mechanism that adjusts the position of the tool assembly in relation to the drive assembly to compensate for changes in stroke length of the drive assembly that result from articulation of the tool assembly.

FIELD

This technology is generally related to surgical devices for endoscopic use and, more specifically, to surgical devices including articulation mechanisms for articulating tool assemblies.

BACKGROUND

Various types of surgical devices used to endoscopically treat tissue are known in the art, and are commonly used, for example, for closure of tissue or organs in transection, resection, and anastomoses procedures, for occlusion of organs in thoracic and abdominal procedures, and for electrosurgically fusing or sealing tissue.

One example of such a surgical device is a surgical stapling device. Typically, surgical stapling devices include tool assembly having an anvil assembly and a cartridge assembly, and a drive assembly. Typically, the drive assembly includes a flexible drive beam and a clamp member that is supported on a distal end of the drive beam. The drive assembly is movable to advance the clamp member through the tool assembly to approximate the cartridge and anvil assemblies and to advance an actuation sled through the cartridge assembly to eject staples from the cartridge assembly.

During laparoscopic or endoscopic surgical procedures, access to a surgical site is achieved through a small incision or through a narrow cannula inserted through a small entrance wound in a patient. Because of limited area available to access the surgical site, many endoscopic devices include mechanisms for articulating the tool assembly of the device in relation to a body portion of the device to improve access to tissue to be treated. When the tool assembly is in an articulated position pivoted about a pivot axis, the drive beam bends in relation to the pivot axis as the drive assembly is advanced to advance the clamp member through the tool assembly. This bending of the drive beam in relation to the pivot axis changes a stroke length of the drive beam required to fully actuate the tool assembly. In order to compensate for this change in stroke length, increased dead space in the tool assembly is required.

A continuing need exists in the art for an articulating mechanism for a surgical device that minimizes the need for dead space in the tool assembly.

SUMMARY

Some aspects of this disclosure are directed to a surgical device that includes an adapter assembly and a tool assembly that is coupled to the adapter assembly by a pivot member to facilitate articulation of the tool assembly in relation to the adapter assembly. The adapter assembly supports a drive assembly for actuating or firing the tool assembly. The adapter assembly includes an articulation mechanism that adjusts the position of the tool assembly in relation to the drive assembly to compensate for changes in stroke length of the drive assembly that result from articulation of the tool assembly.

One aspect of this disclosure is directed to a surgical stapling device including a tool assembly and an adapter assembly. The tool assembly defines a first longitudinal axis and has an anvil and a cartridge assembly. The anvil is coupled to the cartridge assembly to facilitate movement of the tool assembly between an open position and a clamped position. The adapter assembly defines a second longitudinal axis and includes an outer tube, a drive assembly and an articulation mechanism. The outer tube has a proximal portion and a distal portion. The distal portion of the outer tube supports the tool assembly such that the tool assembly is movable from a non-articulated position in which the first longitudinal axis of the tool assembly is aligned with the second longitudinal axis of the adapter assembly, and an articulated position in which the first longitudinal axis of the tool assembly is misaligned with the second longitudinal axis of the adapter assembly. The drive assembly has a flexible beam and a clamp member. The flexible beam has a proximal portion and a distal portion. The clamp member is supported on the distal portion of the flexible beam. The drive assembly is movable between a retracted position and an advanced position to move the clamp member through the tool assembly to move the tool assembly from the open position to the clamped position and to eject staples from the cartridge assembly. The articulation mechanism includes an adapter cam and first and second articulation links. The adapter cam defines a first cam channel, a second cam channel, and a third cam channel. The first articulation link has a distal portion coupled to the tool assembly and a proximal portion that supports a first cam member that is received within the first cam channel of the adapter cam. The second articulation link has a distal portion coupled to the tool assembly and a proximal portion that supports a second cam member that is received within the second cam channel of the adapter cam. The proximal portion of the outer tube supports a third cam that is received within the third cam channel of the adapter cam, wherein movement of the adapter cam causes movement of the first and second articulation links to move the tool assembly between the non-articulated position and the articulated position and causes movement of the outer tube in relation to the drive assembly to change a position of the tool assembly in relation to the drive assembly.

Another aspect of this disclosure is directed to a surgical device including a tool assembly, and an adapter assembly. The tool assembly defines a first longitudinal axis and has a first jaw and a second jaw. The first jaw is coupled to the second jaw to facilitate movement of the tool assembly between an open position and a clamped position. The adapter assembly defines a second longitudinal axis and includes an outer tube, a drive assembly, and an articulation mechanism. The outer tube has a proximal portion and a distal portion. The distal portion of the outer tube supports the tool assembly such that the tool assembly is movable from a non-articulated position in which the first longitudinal axis of the tool assembly is aligned with the second longitudinal axis of the adapter assembly, and an articulated position in which the first longitudinal axis of the tool assembly is misaligned with the second longitudinal axis of the adapter assembly. The drive assembly has a flexible beam and a clamp member. The flexible beam has a proximal portion and a distal portion. The clamp member is supported on the distal portion of the flexible beam. The drive assembly is movable between a retracted position and an advanced position to move the clamp member through the tool assembly to move the tool assembly from the open position to the clamped position. The articulation mechanism includes an adapter cam and an articulation link. The adapter cam defines a first cam channel and a second cam channel. The articulation link has a distal portion coupled to the tool assembly and a proximal portion that supports a first cam member that is received within the first cam channel of the adapter cam. The proximal portion of the outer tube supports a second cam that is received within the second cam channel of the adapter cam. Movement of the adapter cam causes movement of the articulation link to move the tool assembly between the non-articulated position and the articulated position and causes movement of the outer tube in relation to the drive assembly to change a position of the tool assembly in relation to the drive assembly.

Yet another aspect of this disclosure is directed to a surgical stapling device including a handle assembly, a tool assembly, and an adapter assembly. The tool assembly defines a first longitudinal axis and has a first jaw and a second jaw. The first jaw is coupled to the second jaw to facilitate movement of the tool assembly between an open position and a clamped position. The adapter assembly is supported on the handle assembly and defines a second longitudinal axis. The adapter assembly includes an outer tube and an articulation mechanism. The outer tube has a distal portion that supports the tool assembly. The articulation mechanism includes an adapter cam and an articulation link. The adapter cam defines a first cam channel and a second cam channel. The articulation link has a distal portion coupled to the tool assembly and a proximal portion that supports a first cam member that is received within the first cam channel of the adapter cam. The proximal portion of the outer tube supports a second cam that is received within the second cam channel of the adapter cam. Movement of the adapter cam causes movement of the articulation link to move the tool assembly between a non-articulated position and an articulated position and causes longitudinal movement of the outer tube in relation to adapter cam to change a position of the tool assembly in relation to the handle assembly.

In aspects of the disclosure, the adapter cam is cylindrical and defines a longitudinal through bore.

In some aspects of the disclosure, the proximal portion of the outer tube is received within the longitudinal through bore of the adapter cam.

In certain aspects of the disclosure, the first and second cam channels are configured to drive the first and second articulation links in opposite directions to each other.

In aspects of the disclosure, the adapter assembly includes an inner support tube that supports the first and second articulation links within the outer tube.

In some aspects of the disclosure, the first and second articulation links include curved inner surfaces that engage an outer surface of the inner support tube.

In certain aspects of the disclosure, the adapter assembly includes a pivot assembly for pivotally coupling the tool assembly to the outer tube of the adapter assembly.

In aspects of the disclosure, the pivot assembly includes a mounting portion and first and second pivot links.

In some aspects of the disclosure, the mounting portion is secured to the tool assembly and is pivotally coupled to the distal portion of the outer tube.

In certain aspects of the disclosure, the mounting portion defines a longitudinal slot to facilitate passage of the drive assembly.

In aspects of the disclosure, the first pivot link has a proximal portion coupled to the first articulation link and a distal portion coupled to the mounting portion of the pivot assembly, and the second pivot link has a proximal portion coupled to the second articulation link and a distal portion coupled to the mounting portion of the pivot assembly.

In some aspects of the disclosure, the first and second pivot links are positioned on opposite sides of the flexible beam of the drive assembly and define a channel that is aligned with the longitudinal slot formed in the mounting portion.

In certain aspects of the disclosure, each of the first and second pivot links has an inner guide surface that engages the flexible beam of the drive assembly.

In aspects of the disclosure, the inner guide surfaces of the first and second pivot links is substantially linear.

In some aspects of the disclosure, the stapling device includes a drive member that is engaged with the drive assembly to move the drive assembly between its retracted and advanced positions.

In certain aspects of the disclosure, the drive member is a drive screw.

In aspects of the disclosure, a coupling member is supported on the distal portion of the outer tube and defines a clevis that is pivotally coupled to the mounting portion.

Other features of the disclosure will be appreciated from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of the disclosure are described herein below with reference to the drawings, wherein:

FIG. 1 is a side perspective view of a surgical stapling device including aspects of the disclosure with the stapling device in a non-articulated position and shown in phantom in an articulated position;

FIG. 2 is a side perspective view of the adapter assembly and tool assembly of the surgical stapling device shown in FIG. 1 in a non-articulated position with a rotation knob and the tool assembly shown in phantom;

FIG. 3 is a side perspective, exploded view of the adapter assembly shown in FIG. 2;

FIG. 4 is an enlarged view of the indicated area of detail shown in FIG. 3 illustrating a barrel cam of the adapter assembly;

FIG. 5 is a side perspective view of the barrel cam shown in FIG. 4 rotated 180 degrees;

FIG. 6 is a side perspective view of a drive assembly of the adapter assembly shown in FIG. 3;

FIG. 7 is a side perspective view of the adapter assembly and tool assembly shown in FIG. 1 with the tool assembly in a non-articulated position;

FIG. 8 is an enlarged view of the indicated area of detail shown in FIG. 7;

FIG. 9 is a side perspective view of the tool assembly and distal portion of the adapter assembly shown FIG. 7 with an anvil assembly removed from the tool assembly;

FIG. 10 is a cross-sectional view taken along section line 10-10 of FIG. 7;

FIG. 11 is an enlarged view of the indicated area of detail shown in FIG. 10;

FIG. 12 is an enlarged view of the indicated area of detail shown in FIG. 10;

FIG. 13 is a cross-sectional view taken through the adapter assembly and tool assembly shown in FIG. 7 with the tool assembly in an articulated position; and

FIG. 14 is an enlarged view of the indicated area of detail shown in FIG. 13.

DETAILED DESCRIPTION

The disclosed surgical stapling device will now be described in detail with reference to the drawings in which like reference numerals designate identical or corresponding elements in each of the several views. However, it is to be understood that the aspects of the disclosure are merely exemplary of the disclosure and may be embodied in various forms. Well-known functions or constructions are not described in detail to avoid obscuring the disclosure in unnecessary detail. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the disclosure in virtually any appropriately detailed structure. In addition, directional terms such as front, rear, upper, lower, top, bottom, distal, proximal, and similar terms are used to assist in understanding the description and are not intended to limit the disclosure.

In this description, the term “proximal” is used generally to refer to that portion of the device that is closer to a clinician, while the term “distal” is used generally to refer to that portion of the device that is farther from the clinician. In addition, the term “clinician” is used generally to refer to medical personnel including doctors, nurses, and support personnel.

The disclosed surgical device includes an adapter assembly and a tool assembly that is coupled to the adapter assembly by a pivot member to facilitate articulation of the tool assembly in relation to the adapter assembly. The adapter assembly includes a drive assembly having a resilient drive beam and a clamp member that is positioned within the tool assembly. The drive assembly is movable between retracted and advanced positions over a stroke length to advance the clamp member within the tool assembly to move the tool assembly from an open position to a clamped position and to eject staples from the tool assembly. The stroke length required to fully actuate the tool assembly changes as the tool assembly is articulated. The adapter assembly includes an articulation mechanism that adjusts the position of the tool assembly in relation to the drive assembly to compensate for this change in stroke length.

FIG. 1 illustrates a surgical device according to aspects of the disclosure shown generally as surgical device 10. The surgical device 10 includes a handle assembly 12, an adapter assembly 14, and a tool assembly 16. The adapter assembly 14 defines a longitudinal axis “X” (FIG. 1) and the tool assembly defines a longitudinal axis “Y”. The tool assembly 16 is pivotally coupled to the adapter assembly 14 and can pivot between a non-articulated position (FIG. 1) in which the longitudinal axes “X” and “Y” of the adapter and anvil assemblies 14 and 16, respectively, are aligned with each other to articulated positions (shown in phantom in FIG. 1) in which the longitudinal axes “X” and “Y” of the adapter and tool assemblies 14 and 16, respectively, are misaligned with each other. The handle assembly 12 includes a body 12 a that defines a stationary handle 18 and actuation buttons 20 that are operable to initiate operation of the surgical device 10, i.e., approximation of the tool assembly 16, articulation of the tool assembly 16, and firing of staples from the tool assembly 16. The handle assembly 12 supports a rotation knob 22 that is coupled to a proximal portion 14 a of the adapter assembly 14 and is rotatable to rotate the adapter assembly 14 and the tool assembly 16 in relation to the handle assembly 12 about the longitudinal axis “X”. While the depicted surgical device 10 may be configured to fire staples, it is contemplated that the surgical device 10 may be adapted to fire any other suitable fastener such as clips and two-part fasteners. While the figures depict a linear surgical device 10, it is envisioned that certain components described herein may be adapted for use in other types of endoscopic surgical instruments including surgical stapling devices with non-linear tool assemblies, endoscopic forceps, graspers, dissectors, other types of surgical stapling instruments, powered vessel sealing and/or cutting devices, etc.

FIGS. 1-3 illustrate the tool assembly 16 which includes an anvil 24 and a cartridge assembly 26. The anvil 24 is coupled to the cartridge assembly 26 by a pivot member 28 (FIG. 9) that facilitates movement of the anvil 24 in relation to the cartridge assembly 26 between open and clamped positions. Although the cartridge assembly 26 is shown to pivot in relation to the anvil 24, it is envisioned that the cartridge assembly 26 could be stationary and the anvil 24 could pivot in relation to the cartridge assembly 26. The anvil 24 includes a proximal portion that supports or includes a bracket 30. The bracket 30 (FIG. 3) supports a pivot pin 32 that extends radially outward from the bracket 30 in a direction away from the cartridge assembly 26.

FIGS. 2 and 3 illustrate the adapter assembly 14 which includes an outer tube 40, a coupling member 42, a pivot assembly 44, an articulation mechanism 46, and a drive assembly 48 (FIG. 6). The outer tube 40 has a proximal portion 40 a and a distal portion 40 b. The proximal portion 40 a of the outer tube 40 is coupled to the articulation mechanism 46 and is described in further detail below. The distal portion 40 b of the outer tube 40 supports the coupling member 42. The coupling member 42 includes a proximal portion that is received within the distal portion 40 b of the outer tube 40 and distal portion that supports the tool assembly 16. In aspects of the disclosure, the proximal portion of the coupling member 42 is fixedly secured within the distal portion 40 b of the outer tube 40 by pins 49. The distal portion of the coupling member 42 defines a clevis 50 that pivotally supports the pivot assembly 44 and the tool assembly 16 as described below. The clevis 50 includes spaced fingers 52 that define openings 52 a.

The pivot assembly 44 includes a mounting portion 58 and first and second pivot links 60 a and 60 b. The mounting portion 58 defines a longitudinal slot 62 and includes a proximally extending bracket 66 that supports a pivot member 68. The longitudinal slot 62 of the mounting portion 58 has an inwardly curved proximal end 64 that has a width that decreases in the distal direction. The longitudinal slot 62 receives the drive assembly 48 (FIG. 6). The curved proximal end 64 of the longitudinal slot 62 provides a support surface for the drive assembly 48 when the tool assembly 16 is articulated. The pivot member 68 is received within the opening 52 a of one of the fingers 52 of the clevis 50 of the coupling member 42. The coupling member 44 has a distal portion that is received within and fixedly secured to the proximal portion of the anvil 24 by pins (not shown). The pivot pin 32 of the bracket 30 on the proximal portion of the anvil 24 is received within the other opening 52 a of the other spaced finger 52 of the clevis 50 of the coupling member 42 to pivotally secure the tool assembly 16 to the clevis 50 of the coupling member 42.

Each of the first and second pivot links 60 a and 60 b includes an inner guide surface 70, a distal portion 72, and a proximal portion 74. The inner guide surface 70 is substantially linear and the distal and proximal portions 72 and 74 curve outwardly in a direction away from the guide surface 70 such that the first and second pivot links have a flattened C-shape configuration. The distal portion 72 of the first pivot link 60 a is pivotally coupled to the mounting portion 58 on a first side of the longitudinal slot 62 by a pivot member 75 a and the distal portion of the second pivot link 60 a is pivotally coupled to the mounting portion 58 on a second side of the longitudinal slot 62 by a pivot member 75 b. The proximal portions 74 of the first and second pivot links 60 a and 60 b are coupled to the articulation mechanism 46 as described below. It is noted that the pivot links 60 a and 60 b are secured to the mounting portion 58 such that the inner guide surfaces 70 of the pivot links 60 a and 60 b face each other and are positioned proximally of the longitudinal slot 62 to define a channel 70 a that leads into the longitudinal slot 62 (FIG. 12) of the mounting portion 58.

The articulation mechanism 46 includes an adapter cam 80, first and second articulation links 82 and 84, and an inner support tube 86. The first articulation link 82 includes a first link portion 82 a and a second link portion 82 b which are fixedly coupled together by pins or rivets (not shown) Similarly, the second articulation link 84 includes a first link portion 84 a and a second link portion 84 b which are fixedly coupled together by pins or rivets (not shown). It is envisioned that the first and second articulation links 82 and 84 could be integrally formed as a single piece. The first articulation link 82 has a distal portion that is coupled to the proximal portion 74 of the first pivot link 60 a by a pivot pin 86 and the second articulation link 84 has a distal portion that is coupled to the proximal portion 74 of the second pivot link 60 b by a pivot pin 88. Each of the first and second articulation links 82 and 84 includes a curved inner surface 90 that is engaged with an outer surface of the inner support tube 86 such that the first and second articulation links 82 and 84 are movably supported along the outer surface of the inner support tube 86 within the outer tube 40 (FIG. 11).

The proximal portion of each of the articulation links 82 and 84 supports an inwardly extending cam member 92 and 94, respectively. The cam members 92 and 94 are engaged with the adapter cam 80 as described below such that movement of the adapter cam 80 causes longitudinal movement of the first and second articulation links 82 and 84 within the outer tube 40.

FIGS. 3-5, 7 and 8 illustrate the adapter cam 80. In aspects of the disclosure, the adapter or barrel cam 80 includes a cylindrical body 100 that defines a longitudinal through bore 80 a and three cam channels. It is envisioned that the adapter or barrel cam could have a variety of different configurations rather than cylindrical or barrel-shaped. The three cam channels include a first cam channel 102, a second cam channel 104, and a third cam channel 106. The barrel cam 80 is axially fixed and rotatably supported in a proximal portion of the adapter assembly 14. Although not shown, the barrel cam 80 is coupled to the handle assembly 12 (FIG. 1) via gears or the like such that the barrel cam 80 can be selectively rotated in a clockwise or counter-clockwise direction.

The longitudinal bore 80 a of the barrel cam 80 receives the inner support tube 86, the first and second articulation links 82 and 84, and the outer tube 40. The first cam channel 102 receives the cam member 92 of the first articulation link 82 and the second cam channel 104 of the barrel cam 80 receives the cam member 94 of the second articulation link 84. The first and second cam channels 102 and 104, respectively, are angled in different directions along the longitudinal axis “X” of the adapter assembly 14 such that rotation of the barrel cam 80 moves the first and second articulation links 82 and 84 longitudinally in opposite directions within the outer tube 40 along the inner support tube 86. As described above, the distal portions of the first and second articulation links 82 and 84, respectively, are coupled to opposite sides of the mounting portion 58 of the adapter assembly 14. As the articulation links 82 and 84 are moved in opposite directions, the mounting portion 58 is pivoted about a transverse axis “Z” (FIG. 1) defined by the pivot member 68 of the mounting portion 58. The tool assembly 16 is supported on the mounting portion 58. Thus, pivotal movement of the mounting portion 58 causes pivotal movement of the tool assembly 16.

The proximal portion 40 a of the outer tube 40 supports a cam member 110 that extends radially outwardly from the outer tube 40 within the longitudinal bore 80 a of the barrel cam 80 into the third cam channel 106 of the cam barrel 80. In aspects of the disclosure, the cam member 110 is secured within a bore 112 formed in the outer tube 40. Alternately, the cam member 110 can be integrally formed with the outer tube 40. In some aspects of the disclosure, a reinforcement member 114 is supported within the outer tube 40 and defines a bore 116 that receives the cam member 110 to provide added support to the outer tube 40. The outer tube 40 may also include a cover 120 that is received about a proximal portion of the barrel cam 80 to enclose the third cam channel 106. The third cam channel 106 is configured to advance or retract the outer tube 40 in relation to the handle assembly 12 and the barrel cam 80 upon rotation of the barrel cam 80 within the adapter assembly 14.

The inner support tube 86 supports a ring 124 that is secured to the inner support tube 86 and is positioned distally of the barrel cam 80 to prevent distal movement of the barrel cam 80 within the adapter assembly 14. A shim 126 is positioned between the barrel cam 80 and the ring 124 to minimize friction between the barrel cam 80 and the ring 124. In aspects of the disclosure, the ring 124 and the barrel cam 80 can be formed of a metal such as stainless steel, and the shim can be formed of plastic or other material having a low coefficient of friction.

FIG. 6 illustrates the drive assembly 48 which includes a clamp member 130, a flexible beam 132, a rigid beam 134, and a coupling member 136. The drive assembly 48 extends through the inner support tube 86 of the articulation mechanism 46. The clamp member 130 is configured to move through the tool assembly 16 to actuate the tool assembly 16 as known in the art. In aspects of the disclosure, the clamp member 130 includes a first beam 138, a second beam 140, and a vertical strut 142. The vertical strut 142 includes a knife blade 144. When the clamp member 130 is advanced through the tool assembly 16, the first beam 138 of the clamp member 130 engages the anvil 24 and the second beam 140 of the clamp member 130 engages the cartridge assembly 26 to move the tool assembly 16 to the clamped position (FIG. 1). As the clamp member 130 moves through the tool assembly 16, the vertical strut 142 engages an actuation sled (not shown) to eject staples from the cartridge assembly 26 (FIG. 1). For a detailed description of exemplary aspects of the construction and operation of a clamp member, see U.S. Pat. No. 6,241,139.

The flexible beam 132 includes a distal end that is secured to the clamp member 130 and a proximal end that is secured to the rigid beam 134. The flexible beam 132 is formed of a material that allow the beam 132 to bend when the tool assembly 16 is moved to an articulated position (FIG. 13) to allows the clamp member 130 to move along the longitudinal axis “Y” (FIG. 1) of the tool assembly 16 as the tool assembly 16 is actuated, e.g., spring steel. The rigid beam 134 defines a blind bore 140 (FIG. 13) and is secured to the coupling member 136. The coupling member 136 defines a threaded channel 142 that is aligned with the blind bore 140.

The adapter assembly 14 includes a drive screw 144 that includes a distal threaded portion 146 that is received within the threaded channel 142 of the coupling member 136 and extends into the blind bore 140 of the rigid beam 134. The drive screw 144 includes a proximal portion 148 that extends into the handle assembly 12 (FIG. 1). Although not shown, the handle assembly 12 includes a mechanism to rotate the drive screw 144 within the coupling member 136 of the drive assembly 48 to move the drive assembly 48 within the adapter assembly 14 and the tool assembly 16 to actuate the tool assembly 16.

FIGS. 10 and 13 illustrate the distance or stroke length that the drive assembly 46 must travel to fully actuate the tool assembly 16, i.e., eject all of the staples from the cartridge assembly. The stroke length “X1” (FIG. 10) when the tool assembly 16 is in a non-articulated positon differs from the stroke length “X2”. The reason for this difference is that when the tool assembly 16 is in the non-articulated position, the drive assembly 46 follows a straight line along the longitudinal axis “X” of the adapter assembly 14 and through the transverse pivot axis “Z” of the tool assembly 16 to the distal portion of the tool assembly 16. When the tool assembly 16 is articulated (FIG. 13), the first and second pivot links 60 a and 60 b direct the flexible beam 132 along a path that is inwardly of the transverse pivot axis “Z”, thus shortening the distance that the drive assembly 46 must travel to fully actuate the tool assembly 16. This difference increases along a parabolic curve such that the difference increases at a greater rate as the degree of articulation increases. In known devices, in order to compensate for this distance, the length of the tool assembly 16 had to be increased to include dead space to house the clamp member 130 of the drive assembly 46. As used herein, “dead space” is the portion of the tool assembly that does not include staples for suturing tissue. This disclosure addresses this issue by providing an articulation mechanism that can change the position of the tool assembly in relation to the drive assembly during articulation to compensate for the change in stroke length of the drive assembly.

FIGS. 9-12 illustrate the adapter assembly 14 and the tool assembly 16 in a non-articulated position with the drive assembly 48 in a fully advanced position. In the fully advanced position, the clamp member 130 is positioned at a distal end of a knife slot 200 (FIG. 9) in a staple cartridge 202 of the cartridge assembly 26. In the non-articulated position, the cam member 92 of the first articulation link 82 is received in the first cam channel 102 of the barrel cam 80 (FIG. 11), the cam member 94 of the second articulation link 84 is received within the cam channel 104 of the barrel cam 80, and the cam member 110 is received within the cam channel 106 of the barrel cam 80.

FIGS. 13 and 14 illustrate the adapter assembly 14 and the tool assembly 16 as the tool assembly 16 is articulated in the direction of arrow “H” in FIG. 13 about the transverse pivot axis “Z”. When the barrel cam 80 is rotated via operation of the handle assembly 12 (FIG. 1) in the direction of arrow “C” in FIGS. 13 and 14, the cam members 92 and 94 are moved within the cam channels 102 and 104, respectively, in different directions to move the first articulation link 82 in the direction of arrow “D” in FIG. 14 and to move the second cam link 84 in the direction of arrow “E” in FIG. 14. As described above, the distal portions of the first and second cam links 82 and 84 are coupled to the pivot links 60 a and 60 b. When the first and second articulation links 82 and 84 are moved in directions D and E (FIG. 13), the first pivot link 60 a is pulled in the direction of arrow “F” in FIG. 13 and the second pivot link 60 b is pushed in the direction of arrow “G” in FIG. 13. This movement of the first and second pivot links 60 a and 60 b causes the tool assembly 16 to pivot about the transverse axis “Z” in the direction of arrow “H”. As can be seen in FIG. 13, the guide surfaces 70 of the first and second pivot links 60 a and 60 b define the channel 70 a through which the flexible beam 132 extend. The channel 70 a is offset inwardly from the pivot axis “Z” of the tool assembly 16. As described above, this shortens the required stroke length of the drive assembly 48 to actuate the tool assembly 16.

In order to compensate for the change in drive assembly stroke length from “X1” (FIG. 10) to “X2”, the cam member 110, which is positioned within the cam channel 106 in the barrel cam 80 is moved distally along the cam channel 106 in the direction of arrow “I” in FIG. 14 to advance the outer tube 40 in relation to the drive assembly 48. As the outer tube 40 moves distally about the drive assembly 48 in relation to the barrel cam 80, the length of the adapter assembly 14 is adjusted to compensate for the change in stroke length. It is noted that the configuration of the cam channel 106 in the barrel cam 80 is such that the adjustment of the length of the adapter assembly occurs to a greater degree as the degree of articulation is increased.

Persons skilled in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary aspects of the disclosure. It is envisioned that the elements and features illustrated or described in connection with one exemplary embodiment may be combined with the elements and features of another without departing from the scope of the present disclosure. As well, one skilled in the art will appreciate further features and advantages of the disclosure based on the above-described aspects of the disclosure. Accordingly, the disclosure is not to be limited by what has been particularly shown and described, except as indicated by the appended claims. 

What is claimed is:
 1. A surgical stapling device comprising: a tool assembly defining a first longitudinal axis and having an anvil and a cartridge assembly, the anvil coupled to the cartridge assembly to facilitate movement of the tool assembly between an open position and a clamped position; and an adapter assembly defining a second longitudinal axis and including: an outer tube having a proximal portion and a distal portion, the distal portion of the outer tube supporting the tool assembly such that the tool assembly is movable from a non-articulated position in which the first longitudinal axis of the tool assembly is aligned with the second longitudinal axis of the adapter assembly, and an articulated position in which the first longitudinal axis of the tool assembly is misaligned with the second longitudinal axis of the adapter assembly; a drive assembly having a flexible beam and a clamp member, the flexible beam having a proximal portion and a distal portion, the clamp member supported on the distal portion of the flexible beam, the drive assembly movable between a retracted position and an advanced position to move the clamp member through the tool assembly to move the tool assembly from the open position to the clamped position and to eject staples from the cartridge assembly; an articulation mechanism including an adapter cam and first and second articulation links, the adapter cam defining a first cam channel, a second cam channel, and a third cam channel, the first articulation link having a distal portion coupled to the tool assembly and a proximal portion that supports a first cam member that is received within the first cam channel of the adapter cam, the second articulation link having a distal portion coupled to the tool assembly and a proximal portion that supports a second cam member that is received within the second cam channel of the adapter cam, and the proximal portion of the outer tube supporting a third cam that is received within the third cam channel of the adapter cam, wherein movement of the adapter cam causes movement of the first and second articulation links to move the tool assembly between the non-articulated position and the articulated position and causes movement of the outer tube in relation to the drive assembly to change a position of the tool assembly in relation to the drive assembly.
 2. The surgical stapling device of claim 1, wherein the adapter cam is cylindrical and defines a longitudinal through bore.
 3. The surgical stapling device of claim 2, wherein the proximal portion of the outer tube is received within the longitudinal through bore of the adapter cam.
 4. The stapling device of claim 3, wherein the first and second cam channels are configured to drive the first and second articulation links in opposite directions to each other.
 5. The stapling device of claim 4, wherein the adapter assembly includes an inner support tube that supports the first and second articulation links within the outer tube.
 6. The stapling device of claim 5, wherein the first and second articulation links include curved inner surfaces that engage an outer surface of the inner support tube.
 7. The stapling device of claim 1, wherein the adapter assembly includes a pivot assembly for pivotally coupling the tool assembly to the outer tube of the adapter assembly, the pivot assembly including a mounting portion and first and second pivot links.
 8. The stapling device of claim 7, wherein the mounting portion is secured to the tool assembly and is pivotally coupled to the distal portion of the outer tube, the mounting portion defining a longitudinal slot to facilitate passage of the drive assembly.
 9. The stapling device of claim 8, wherein the first pivot link has a proximal portion coupled to the first articulation link and a distal portion coupled to the mounting portion of the pivot assembly, and the second pivot link has a proximal portion coupled to the second articulation link and a distal portion coupled to the mounting portion of the pivot assembly.
 10. The stapling device of claim 9, wherein the first and second pivot links are positioned on opposite sides of the flexible beam of the drive assembly and define a channel that is aligned with the longitudinal slot formed in the mounting portion.
 11. The stapling device of claim 10, wherein each of the first and second pivot links has an inner guide surface that engages the flexible beam of the drive assembly.
 12. The stapling device of claim 11, wherein the inner guide surface is substantially linear.
 13. The stapling device of claim 1, further including a drive member engaged with the drive assembly to move the drive assembly between its retracted and advanced positions.
 14. The stapling device of claim 13, wherein the drive member is a drive screw.
 15. The stapling device of claim 8, further including a coupling member supported on the distal portion of the outer tube, the coupling member defining a clevis that is pivotally coupled to the mounting portion.
 16. A surgical device comprising: a tool assembly defining a first longitudinal axis and having a first jaw and a second jaw, the first jaw coupled to the second jaw to facilitate movement of the tool assembly between an open position and a clamped position; and an adapter assembly defining a second longitudinal axis and including: an outer tube having a proximal portion and a distal portion, the distal portion of the outer tube supporting the tool assembly such that the tool assembly is movable from a non-articulated position in which the first longitudinal axis of the tool assembly is aligned with the second longitudinal axis of the adapter assembly and an articulated position in which the first longitudinal axis of the tool assembly is misaligned with the second longitudinal axis of the adapter assembly; a drive assembly having a flexible beam and a clamp member, the flexible beam having a proximal portion and a distal portion, the clamp member supported on the distal portion of the flexible beam, the drive assembly movable between a retracted position and an advanced position to move the clamp member through the tool assembly to move the tool assembly from the open position to the clamped position; an articulation mechanism including an adapter cam and an articulation link, the adapter cam defining a first cam channel and a second cam channel, the articulation link having a distal portion coupled to the tool assembly and a proximal portion that supports a first cam member that is received within the first cam channel of the adapter cam, the proximal portion of the outer tube supporting a second cam that is received within the second cam channel of the adapter cam, wherein movement of the adapter cam causes movement of the articulation link to move the tool assembly between the non-articulated position and the articulated position and causes movement of the outer tube in relation to the drive assembly to change a position of the tool assembly in relation to the drive assembly.
 17. The surgical device of claim 16, wherein the adapter cam is cylindrical and defines a longitudinal through bore.
 18. The surgical device of claim 17, wherein the proximal portion of the outer tube is received within the longitudinal through bore of the adapter cam.
 19. A surgical device comprising: a handle assembly; a tool assembly defining a first longitudinal axis and having a first jaw and a second jaw, the first jaw coupled to the second jaw to facilitate movement of the tool assembly between an open position and a clamped position; and an adapter assembly supported on the handle assembly and defining a second longitudinal axis, the adapter assembly including an outer tube and an articulation mechanism, the outer tube having a distal portion that supports the tool assembly, the articulation mechanism including an adapter cam and an articulation link, the adapter cam defining a first cam channel and a second cam channel, the articulation link having a distal portion coupled to the tool assembly and a proximal portion that supports a first cam member that is received within the first cam channel of the adapter cam, the outer tube having a proximal portion supporting a second cam that is received within a second cam channel of the adapter cam, wherein movement of the adapter cam causes movement of the articulation link to move the tool assembly between a non-articulated position and an articulated position and causes longitudinal movement of the outer tube in relation to the adapter cam to change a position of the tool assembly in relation to the handle assembly.
 20. The surgical device of claim 19, further including an anvil supported on the first jaw and a cartridge assembly supported on the second jaw. 